100 dollar *

1. Unit Factor Method How many quarters can I get for a 100 dollar bill? 1 4 quarters 1 dollar 4 quarters = 1 dollar 1 dollar 1 dollar =1 4 quarters 1 dollar 100 dollar * = 400 quarters

2. What is my height in meters and centimeters? 1 2.54 cm = 1 in. 1 in. 1 in. 61.5 in. 1.56*102 cm 1 2.54 cm 1 in. 100 cm = 1 m 100 cm 100 cm = 156 cm 61.5 in. * 1 m 100 cm = 1.56 m 156 cm *

3. Specific Gravity % Composition Density (substance) (water) Parts of A 100 parts mixture Sp. Gr.= mass (g) volume (ml) %A = = (water)=1.00 g/ml @ 25oC A concentrated hydrochloric acid solution is 36.31% HCl and 63.69% H2O by mass. Its specific gravity is 1.185. What mass of pure HCl is contained in 175 ml of this solution? 1.185 g/ml of solution 1.00 g/ml of water 36.31 g of HCl 100 g of soln. (soln)1.185 g/ml ; 36.31 g of HCl1.185 g of soln. 175ml of soln. = 75.3g of HCl 100 g of soln. ml of soln.  

4. Stoichiometry Composition Stoichiometry-Quantitative relationship among elements in a compound. (H2O; 2 H atom and 1 O atom per 1 H2O molecule) Reaction Stoichiometry-Quantitative relationship among substances as they undergo chemical changes. (P4+6Cl2 4PCl3; 1P4 molecule reacts with 6Cl2 molecules to produce 4 PCl3 molecules) Dalton’s Atomic Theory: 1) An element is composed of extremely small, indivisible particles called atoms 2) All atoms of a given element have identical properties 3) Atoms cannot be created, destroyed or transformed into atoms of another element. 4) Compounds are formed when atoms of different elements combine with one another in small whole-number ratios. 5) The relative numbers and kinds of atoms are constant in a given compound.

5. Atom-the smallest particle of an element that maintains its chemical identity through all chemical and physical changes Atomic Number (Z)-# of protons in the nucleus and it defines the atom.

6. Molecule-the smallest particle of an element or compound that can have a stable independent existence. Monotomic molecules -The noble gases: He, Ne, Ar ... Diatomic molecules - O2, N2, H2, F2, I2, Br2, Cl2 .....(Know these) Triatomic molecules - O3, H2O, CO2 ...... molecular oxygen (O2) and ozone (O3) are allotropes-different forms of the same element in the same physical state. Structural Formula Ball-and-Stick Model   Chemical Formulas

7. Formula units: Ionic Compounds-consists of an extended array of ions KBr=K+ ions and Br - ions ; Potassium Bromide Know Table 2-3 in the book Cat=+ Magnesium Floride Mg2+ F - MgF2

8. 2Na+Cl2 2NaCl Na+ Cation NaCl Sodium Chloride Cl- Anion

9. Atomic Weight atomic mass unit (amu) - arbitrary unit defined by scientists: 1amu=1/12 mass of Carbon-12 atom This is the scale that was used to determine the atomic mass (weight) of every atom listed in the periodic table. (H=1.0079amu, O=15.9994..) molecular weight (MW) of water (H2O) = 2*(1.01amu)+(16.0amu)=18.0amu formula weight (FW) of sodium chloride (NaCl)=23.0amu+35.4amu=58.4amu

10. The Mole 1 mole = 6.022045*1023 particles Avogadro’s number NA AW of O = 16.0 amu/atom = 16.0 g/mole FW of NaCl = 58.4 amu/formula unit = 58.4 g/mole 6.022 *1023 NaCl formula units 6.022 *1023 Na+ ions 6.022 *1023 Cl- ions